Embeddings and vector databases are the engine behind RAG and semantic search — they let computers find things by meaning, not just keywords.
Embeddings & Vector Search
Finding things by meaning, not keywords.
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Meaning as numbers.
A model turns text (or images) into a vector — a list of numbers capturing meaning. Similar meanings produce vectors that sit close together.
Check your understanding
1. What is an embedding?
2. What does semantic search match on?
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The essentials
- Embeddings — an AI model turns text (or images) into a list of numbers (a vector) that captures its meaning. Similar meanings sit close together in vector space.
- Vector database — stores millions of these vectors and finds the nearest ones to a query extremely fast (approximate nearest-neighbour search).
- Semantic search — searching by meaning: "how do I reset my password" matches a doc titled "account recovery" even without shared keywords.
- Platforms — Pinecone, Weaviate, Chroma, and pgvector (which adds vectors to PostgreSQL).
This contrasts with traditional relational databases, which match exact values — a nice link across the Academy.
